Urokinase plasminogen activator secreted by cancer-associated fibroblasts induces tumor progression via PI3K/AKT and ERK signaling in esophageal squamous cell carcinoma

// Baoqing Tian 1, * , Xiaojia Chen 1, * , Huihua Zhang 1, * , Xiaoyan Li 1 , Jiakang Wang 2 , Wei Han 1 , Li-Yi Zhang 3 , Li Fu 4 , Yan Li 5 , Changjun Nie 1 , Ying Zhao 1 , Xuan Tan 1 , Hailong Wang 1 , Xin-Yuan Guan 3, 5 and An Hong 1 1 Institute of Biomedicine & Department of Cell Biology, Jinan University, National Engineering Research Center of Genetic Medicine, Guangdong Provincial Key Laboratory of Bioengineering Medicine, Guangzhou, China 2 Cancer Center of Guangzhou Medical University, Guangzhou, China 3 Department of Clinical Oncology, University of Hong Kong, Hong Kong, China 4 Shenzhen Key Laboratory of translational Medicine of Tumor and Cancer Research Centre, School of Medicine, Shenzhen University, Shenzhen, China 5 Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China * These authors have contributed equally to this work Correspondence to: An Hong, email: tha@jnu.edu.cn Xin-Yuan Guan, email: xyguan@hkucc.hku.hk Keywords: uPA, CAFs, PI3K/AKT, ERK, ESCC Received: September 24, 2016 Accepted: January 13, 2017 Published: March 02, 2017 ABSTRACT Cancer-associated fibroblasts (CAFs) are believed to influence tumor behavior and clinical outcomes. We previously showed that conditioned medium (CM) from CAFs induces proliferation and motility of esophageal squamous cell carcinoma (ESCC) cells. Here, we investigated the molecular mechanisms by which the CAF-secreted proteins induce ESCC development and progression. Using antibody arrays, we identified urokinase plasminogen activator (uPA) as one of the main proteins whose release was increased in CAFs compared to normal fibroblasts (NFs). Immunohistochemical analysis of pathological sections showed that uPA-positive cells were localized at the boundaries of tumor and stroma tissues, in stroma between tumor nests, and within the tumors. Increased stromal uPA levels (132/146 cases) correlated with tumor invasion (p < 0.05) and overall survival of ESCC patients (p < 0.05). In vitro assays showed that uPA promotes ESCC cell proliferation, migration, and invasion via PI3K/AKT and ERK signaling pathways. In vivo , anti-uPA antibody suppressed tumor growth in ESCC xenografts. These results suggest that uPA released from stroma, and especially from CAFs, might be a predictive marker for ESCC diagnosis and prognosis, as well as an effective therapeutic target.